A cold-rolled strip length compensation device and method

Abstract

This invention provides a length compensation device and method for cold-rolled strip steel. The length compensation device includes a base, on which a tension roller for detecting and conveying the strip tension is mounted. A pressure roller for pressing down the strip is also mounted on the base. The strip output from the cold rolling mill is directly sent to subsequent processing after being tensioned by the tension roller, or it is pressed down by the pressure roller driven by a hydraulic cylinder to compensate for its length before being sent to subsequent processing. This invention uses a short hydraulic cylinder drive arm to drive a swing arm to achieve a large stroke and large angle swing action, reducing the size and design stroke of the hydraulic cylinder, greatly improving the dynamic response speed of the hydraulic cylinder, and significantly reducing the rotational inertia of the mechanism. The length compensation response is fast, effectively maintaining stable strip tension, thereby improving the dimensional accuracy of the rolled strip. Moreover, the moving elements are lightweight, and the resistance of mechanical friction has a smaller impact.

Description

Technical Field

[0001] This invention belongs to the field of cold-rolled steel, and specifically relates to a cold-rolled strip length compensation device and method. Background Technology

[0002] When cold-rolling ordinary strip steel, the thinning of the strip causes changes in the tension at the inlet and outlet, and the strip length at the outlet also changes slightly. However, this change is usually small, and in such cases, it can usually be solved by adjusting the speed difference between the mill and the coiler using electrical control. However, when the strip cross-section is irregular, the thickness varies greatly, or the thickness changes in a stepwise manner with periodic increases or decreases, the strip outlet tension changes drastically, which can lead to unstable rolling tension due to sudden changes in strip length during rolling in a short period of time. Summary of the Invention

[0003] The purpose of this invention is to provide a cold-rolled strip length compensation device and method to overcome the above-mentioned technical defects.

[0004] To solve the above-mentioned technical problems, the present invention provides a cold-rolled strip length compensation device, including a base, a tension roller for detecting strip tension and conveying strip is installed on the base, and a pressure roller for pressing down strip is also installed on the base. The strip output from the cold rolling mill is directly sent to subsequent processing after being tensioned by the tension roller or sent to subsequent processing after being pressed down by the pressure roller to compensate for its length.

[0005] Furthermore, a pair of hydraulic cylinders are installed on the base, and the piston rods of the two cylinders are rotatably mounted with swing arms. Between the two swing arms is a pressure roller that spans above the strip, and the two ends of the pressure roller are mounted on the two swing arms.

[0006] Furthermore, each cylinder is equipped with a pressure sensor and a displacement sensor, wherein the pressure sensor is used to detect the thrust of the cylinder and the displacement sensor is used to detect the extension and retraction of the cylinder piston rod.

[0007] Furthermore, the swing arm is divided into two parts according to its length, namely the upper arm and the lower arm. The joint between the upper arm and the lower arm is bent at an obtuse angle and is connected to the base by the first pin. The free end of the lower arm is hinged to the piston rod head of the oil cylinder by the second pin.

[0008] The fixed end of the hydraulic cylinder is mounted to the base via a third pin.

[0009] The present invention also provides a method for compensating the length of cold-rolled strip steel, comprising the following steps:

[0010] Step 1: Install a cold-rolled strip length compensation device at the exit of the cold rolling mill;

[0011] Step 2: Two idlers are also installed above the cold-rolled strip length compensation device, namely the front idler and the rear idler.

[0012] Step 3: The strip output from the cold rolling mill is conveyed to the subsequent processing via tension rollers, front idler rollers, pressure rollers and rear idler rollers in sequence.

[0013] Step 4: When the tension roller system detects an increase in strip tension, the pressure roller presses down on the strip to compensate for the strip length.

[0014] Furthermore, when the tension roller system detects an increase in strip tension, the pressure roller presses down on the strip to compensate for the increased strip length. The specific process is as follows:

[0015] When the tension roller system detects an increase in strip tension of ΔP, it transmits the ΔP value to the PLC. The PLC controls the piston rods of the two cylinders to extend a distance L simultaneously. The displacement sensor detects the extension of the piston rods and feeds it back to the PLC. At this time, the swing arm swings around the first pin shaft, driving the pressure roller to gradually move down and press down on the strip until the tension stabilizes and the strip length is compensated.

[0016] Furthermore, the cold-rolled strip length compensation method also includes, when the tension roll system detects a decrease in strip tension, the pressure roll disengages from the strip to compensate for the strip length, the specific process of which is as follows:

[0017] When the tension roller system detects a decrease in strip tension of ΔP', it transmits the ΔP' value to the PLC. The PLC controls the piston rods of the two cylinders to retract by a distance L' simultaneously. The displacement sensor detects the amount of retraction of the piston rods and feeds it back to the PLC. At this time, the swing arm swings around the first pin shaft, causing the pressure roller to gradually move upward and separate from the strip until the tension stabilizes and the strip length is compensated.

[0018] Furthermore, after the PLC controls the hydraulic cylinder to move according to the extension and retraction amount, the displacement sensor first detects the extension and retraction amount of the piston rod and feeds it back to the PLC, and then the pressure sensor detects the thrust of the piston cylinder and feeds it back to the PLC. If the values ​​fed back by the two sensors are within the preset values ​​of the PLC, the hydraulic cylinder is controlled to continue to move; otherwise, the hydraulic cylinder is controlled to continue to extend or retract until the values ​​fed back by the two sensors are within the preset values ​​of the PLC.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) It has a simple structure and consists of a swing roller, a hydraulic cylinder, a pressure sensor, a displacement sensor, a tension roller, etc.

[0021] (2) Length compensation is real-time and reliable. When the thickness of the strip changes suddenly in the roll gap of the rolling mill, the resulting length change is calculated by the calculation formula and immediately driven to the hydraulic cylinder of the swing pressure roller. The hydraulic cylinder extends or retracts according to the calculated value, that is, the swing pressure roller swings to the set angle to achieve length compensation and maintain stable tension.

[0022] (3) The length compensation response is fast, the motion element is lighter, and the mechanical friction resistance has a smaller impact; at the same time, the use of a short hydraulic cylinder drive arm drives the swing arm to achieve a large stroke and large angle swing action, which reduces the size and design stroke of the hydraulic cylinder, greatly improves the dynamic response speed of the hydraulic cylinder, and also greatly reduces the rotational inertia of the mechanism.

[0023] To make the above description of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a front view of a cold-rolled strip length compensation device.

[0025] Figure 2 This is a cross-sectional view of a cold-rolled strip length compensation device.

[0026] Figure 3 This is a schematic diagram of the hydraulic cylinder.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Base; 2. Swing arm; 3. First pin; 4. Pressure roller; 5. Strip; 6. Hydraulic cylinder; 7. Second pin; 8. Third pin; 9. Pressure sensor; 10. Displacement sensor; 11. Tension roller; 121. Front idler roller; 122. Rear idler roller. Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0030] It should be noted that, in this invention, the upper, lower, left, and right in the figure are regarded as the upper, lower, left, and right of the cold-rolled strip length compensation method described in this specification.

[0031] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0032] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0033] First implementation method:

[0034] This embodiment relates to a cold-rolled strip length compensation device, such as... Figure 1 As shown, the cold-rolled strip length compensation device is installed at the outlet of the cold rolling mill. It mainly includes a base 1, on which a tension roller 11 for detecting strip tension and conveying strip 5 is installed. A pressure roller 4 for pressing down strip 5 is also installed on the base 1. The strip 5 output from the cold rolling mill is directly sent to subsequent processing after being tensioned by the tension roller 11, or it is sent to subsequent processing after being pressed down by the pressure roller 4 to compensate for its length.

[0035] When cold rolling strip steel, the tension roll 11 provides tension to the rolled strip steel. At the same time, the tension roll 11 can also detect the tension of the strip. The detection principle is through the tension sensors at both ends of the roll. However, in the field of cold rolling, the structure of the tension roll 11 and the tension detection are all existing technologies and will not be elaborated here.

[0036] When tension roller 11 detects a sudden increase in strip tension, it controls pressure roller 4 to press down on strip 5, stabilizing the tension of strip 5 and thus compensating for the strip length. When tension roller 11 detects a sudden decrease in strip tension, it controls pressure roller 4 to disengage from strip 5, stabilizing the tension of strip 5 and promptly compensating for the change in strip length caused by the sudden change in strip tension during cold rolling.

[0037] The sudden increase in strip tension can be an order-of-magnitude change, such as a sudden increase from 200 kg to 1 t. It can also be defined according to different strip materials and requirements. The sudden decrease in strip tension is the reverse process of the above change, such as a sudden decrease in strip tension from 1 t to 200 kg.

[0038] See Figure 1 and Figure 2 A pair of hydraulic cylinders 6 are mounted on the base 1. The piston rods of both hydraulic cylinders 6 are rotatably mounted with swing arms 2. Between the two swing arms 2 is a pressure roller 4 that spans above the strip 5. The two ends of the pressure roller 4 are mounted on the two swing arms 2. Specifically:

[0039] The swing arm 2 is divided into two parts according to its length: the upper arm and the lower arm. The upper arm and the lower arm are bent at an obtuse angle and are joined to the base 1 by the first pin 3. The free end of the lower arm is hinged to the piston rod head of the oil cylinder 6 by the second pin 7, and the fixed end of the oil cylinder 6 is installed on the base 1 by the third pin 8.

[0040] The fixed end of hydraulic cylinder 6 can rotate slightly. Using this end as a fulcrum, when the piston rod extends, the entire hydraulic cylinder will deflect, such as... Figure 1 As shown, the dotted line represents the state of the piston rod after it extends and deflects. At this time, the entire swing arm 2 is subjected to an upward thrust and rotates around the first pin 3. The rotation trajectory is as follows. Figure 1 As shown by the dotted line, under the push of the hydraulic cylinder 6, the forearm drives the upper arm to swing downward, and the pressure roller 4 presses the strip 5, continuously applying pressure to the strip 5 to maintain the strip tension stability, thereby improving the dimensional accuracy of the rolled strip.

[0041] like Figure 3 As shown, each hydraulic cylinder 6 is equipped with an external pressure sensor 9 and a built-in displacement sensor 10. The pressure sensor 9 is used to detect the thrust of the hydraulic cylinder, and the displacement sensor 10 is used to detect the extension and retraction of the hydraulic cylinder piston rod. Based on the detection data of these two sensors, the downward pressure applied to the strip 5 can be accurately determined.

[0042] Displacement sensor 10 activates the cylinder rod chamber or plug chamber according to the set displacement, causing the cylinder to push a displacement. After the displacement is reached, it switches to pressure, and pressure measurement is completed by pressure sensor 9.

[0043] Specifically, the working principle of the cold-rolled strip length compensation device is as follows:

[0044] When tension roller 11 detects a sudden increase in strip tension, the built-in displacement sensor 10 of cylinder 6 outputs a value based on the change value according to the calculation relationship. The piston rod of cylinder 6 extends a certain distance, and at the same time, the forearm of swing arm 2 rotates counterclockwise around the third pin 8, driving the upper arm of swing arm 2 and pressure roller 4 to rotate around the first pin 3 to the set position, pressing down on strip 5, so that the tension is stabilized and the length is compensated in time. Conversely, if tension roller 11 detects a sudden decrease in strip tension, the above actions are exactly the opposite, so as to timely compensate for the change in strip length caused by the sudden change in strip tension during cold rolling.

[0045] This embodiment uses a short hydraulic cylinder drive arm to drive the swing arm to achieve a large stroke and large angle swing action, which reduces the size and design stroke of the hydraulic cylinder, greatly improves the dynamic response speed of the hydraulic cylinder, significantly reduces the rotational inertia of the mechanism, has a fast length compensation response, lighter motion elements, and less impact from mechanical friction resistance.

[0046] Second implementation method:

[0047] This embodiment provides a method for compensating the length of cold-rolled strip steel, including the following steps:

[0048] Step 1: Install a cold-rolled strip length compensation device at the exit of the cold rolling mill;

[0049] Step 2: Two support rollers are also installed above the cold-rolled strip length compensation device, namely the front support roller 121 and the rear support roller 122.

[0050] Step 3: The strip 5 output from the cold rolling mill is sequentially conveyed to the subsequent processing via tension roller 11, front idler roller 121, pressure roller 4 and rear idler roller 122.

[0051] Step 4: When the tension roller system detects an increase in strip tension, the pressure roller 4 presses down on the strip 5 to compensate for the strip length. The specific process is as follows:

[0052] When the tension roller system detects an increase in strip tension of ΔP, it transmits the ΔP value to the PLC. The PLC controls the piston rods of the two hydraulic cylinders 6 to extend a distance L simultaneously. The displacement sensor 10 detects the extension of the piston rods and feeds it back to the PLC. At this time, the swing arm 2 swings around the first pin shaft 3, driving the pressure roller 4 to gradually move down and press down on the strip 5 until the tension is stable and the strip length is compensated.

[0053] The cold-rolled strip length compensation method also includes, when the tension roller system detects a decrease in strip tension, the pressure roller 4 disengages from the strip 5 to compensate for the strip length, the specific process of which is as follows:

[0054] When the tension roller system detects a decrease in strip tension of ΔP', it transmits the ΔP' value to the PLC. The PLC controls the piston rods of the two hydraulic cylinders 6 to retract by a distance L' simultaneously. The displacement sensor 10 detects the amount of retraction of the piston rods and feeds it back to the PLC. At this time, the swing arm 2 swings around the first pin 3, driving the pressure roller 4 to gradually move upward and separate from the strip 5 until the tension stabilizes and the strip length is compensated.

[0055] After the PLC controls the hydraulic cylinder 6 to move according to the extension and retraction amount, the displacement sensor 10 first detects the extension and retraction amount of the piston rod and feeds it back to the PLC. Then, the pressure sensor 9 detects the thrust of the piston cylinder and feeds it back to the PLC. If the values ​​fed back by the two sensors are within the preset values ​​of the PLC, the hydraulic cylinder 6 is controlled to continue to move. Otherwise, the hydraulic cylinder 6 is controlled to continue to extend or retract until the values ​​fed back by the two sensors are within the preset values ​​of the PLC.

[0056] Specifically, the PLC pre-stores several sets of variable relationship arrays between tension change value, length compensation value, and cylinder extension / retraction amount, as shown in the table below:

[0057] Tension change value △P / △P' a1 a2 …… an Length compensation value b1 b2 …… bn Hydraulic cylinder extension / retraction range L / L' c1 c2 …… cn

[0058] The above variable correspondence is calculated based on empirical values ​​and formulas. an, bn, and cn can be specific numbers or numerical ranges, and there are no requirements.

[0059] Taking the tension roller 11 detecting a sudden increase of a1 in the strip tension as an example, the tension sensor transmits the tension increase value a1 to the PLC. The PLC retrieves the length compensation value b1 corresponding to a1 and the cylinder extension / retraction amount c1 corresponding to a1, and sends the cylinder extension / retraction amount c1 to the displacement sensor 10. At this time, the PLC controls the two cylinders 6 to extend and retract synchronously. The displacement sensor 10 checks whether the cylinder 6 has reached the extension / retraction amount c1 and feeds the result back to the PLC. When the piston rod extension / retraction amount reaches c1, the cylinder 6 stops extending and retracting. If it has not reached c1, the cylinder 6 is controlled to continue extending and retracting until c1 is reached. At the same time, the pressure sensor 9 detects the pressure value of the hydraulic oil driving the cylinder 6, that is, detects the thrust of the piston cylinder and feeds it back to the PLC. The PLC then adjusts the piston rod extension / retraction amount according to the thrust, thus forming a closed-loop feedback.

[0060] The pressure sensor 9 and the displacement sensor 10 provide dual protection to ensure the stability of the strip tension and the reasonable compensation of the strip length.

[0061] The method of converting the pressure applied by the pressure roller 4 into strip tension is existing technology and will not be elaborated here.

[0062] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A length compensation device for cold-rolled strip steel, characterized in that The application relates to a cold-rolled strip steel length compensation device, which comprises a base (1), a tension roller (11) for detecting strip tension and conveying a strip (5) is arranged on the base (1), a compression roller (4) for pressing the strip (5) is also arranged on the base (1), the strip (5) output from a cold-rolling machine is directly sent to subsequent treatment after being tensioned by the tension roller (11) or is sent to subsequent treatment after the length of the strip (5) is compensated by the compression roller (4); a pair of oil cylinders (6) are arranged on the base (1), the piston rod heads of the two oil cylinders (6) are rotatably provided with swing arms (2), the two swing arms (2) are arranged above the compression roller (4) in a cross mode, and the two ends of the compression roller (4) are arranged on the two swing arms (2); the swing arm (2) is divided into two parts according to length, namely a large arm and a small arm, the joint of the large arm and the small arm is bent at an obtuse angle and is combined on the base (1) through a first pin shaft (3), and the free end of the small arm is hinged to the piston rod head of the oil cylinder (6) through a second pin shaft (7); the fixed end of the oil cylinder (6) is arranged on the base (1) through a third pin shaft (8); A pressure sensor (9) and a displacement sensor (10) are arranged on each oil cylinder (6), the pressure sensor (9) is used for detecting the pushing force of the oil cylinder, and the displacement sensor (10) is used for detecting the extension and retraction amount of the piston rod of the oil cylinder; under the pushing of the oil cylinder (6), the small arm drives the large arm to swing downwards, the compression roller (4) holds the strip (5), the strip (5) is continuously pressed, the strip tension is kept stable, the oil cylinder (6) is a short oil cylinder driving force arm, the swing arm (2) is driven to realize large-stroke and large-angle swinging, the size and design stroke of the oil cylinder are reduced, the dynamic response speed of the oil cylinder is improved, and the rotational inertia of the mechanism is reduced; When the tension roller (11) detects that the strip tension suddenly increases, the compression roller (4) is controlled to press the strip (5), so that the strip tension is stable, and the length of the strip is compensated; when the tension roller (11) detects that the strip tension suddenly decreases, the compression roller (4) is controlled to be separated from the strip (5), so that the strip tension is stable, and the change amount of the length of the strip caused by the sudden change of the strip tension during cold rolling is compensated in time.

2. A method of length compensation of cold-rolled strip steel, characterized in that The application further discloses a cold-rolled strip steel length compensation method, which comprises the following steps: Step one: a cold-rolled strip steel length compensation device is arranged at the outlet of a cold-rolling machine; Step two: two supporting rollers, namely a front supporting roller (121) and a rear supporting roller (122), are arranged above the cold-rolled strip steel length compensation device; Step three: the strip (5) output from the cold-rolling machine is conveyed to subsequent treatment in sequence through the tension roller (11), the front supporting roller (121), the compression roller (4) and the rear supporting roller (122); Step four: when the tension roller system detects that the strip tension increases, the compression roller (4) presses the strip (5) to compensate the length of the strip; When the tension roller system detects that the strip tension increases, the compression roller (4) presses the strip (5) to compensate the length of the strip, and the specific process is as follows: When the tension roller system detects that the strip tension increases by △P, the value of △P is transmitted to the PLC, the PLC controls the piston rods of the two oil cylinders (6) to extend by a distance L at the same time, the displacement sensor (10) detects the extension amount of the piston rods and feeds back to the PLC, at this time the swing arm (2) swings around the first pin shaft (3), drives the pressure roller (4) to gradually move downward and press the strip (5) until the tension is stable and the strip length is compensated; Also includes, when the tension roller system detects that the strip tension decreases, the pressure roller (4) is separated from the strip (5) to compensate the strip length, the specific process is as follows: When the tension roller system detects that the strip tension decreases by △P', the value of △P' is transmitted to the PLC, the PLC controls the piston rods of the two oil cylinders (6) to retract by a distance L' at the same time, the displacement sensor (10) detects the retraction amount of the piston rods and feeds back to the PLC, at this time the swing arm (2) swings around the first pin shaft (3), drives the pressure roller (4) to gradually move upward and separate from the strip (5) until the tension is stable and the strip length is compensated.

3. The length compensation method of a cold-rolled steel strip according to claim 2, wherein, After the PLC controls the oil cylinder (6) to act according to the extension / retraction amount, the displacement sensor (10) detects the extension / retraction amount of the piston rods and feeds back to the PLC, and then the pressure sensor (9) detects the thrust of the piston cylinder and feeds back to the PLC, if the values fed back by the two sensors are within the preset values of the PLC, the oil cylinder (6) is controlled to keep acting, otherwise the oil cylinder (6) is controlled to continue extending or retracting until the values fed back by the two sensors are within the preset values of the PLC.

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